The use of global positioning system (GPS) systems in vehicles is becoming more common. GPS provides routing based on current location data obtained from a plurality of satellites, mapping data, and routing systems. Vehicles often have such systems built in. However, these systems have the inherent disadvantage that computer software, and particularly mapping and routing software, is improving rapidly. Additionally, map data is constantly changing as new roads are opened, exits are opened, closed, or moved, roads closed, etc. In general, built-in systems in vehicles are only refreshed when a user purchases a new vehicle. Therefore, there is a significant disadvantage to providing a built-in system for a vehicle.
One prior art method of overcoming this disadvantage is to provide a portable GPS system, which is then placed in the vehicle, and used in the vehicle.